A liquid delivery device is any device that is capable of delivering a liquid to, or remove a liquid from, a specific receptacle, or a specific container. One commonly used liquid delivery device is a pipette. A pipette (also called a pipet, a micropipette, a pipettor, or a chemical dropper) is a laboratory instrument that is used to transport a measured volume of a liquid. Pipettes are commonly used in molecular biology, as well as in medical tests. Pipettes come in several designs for various purposes, having differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Many pipettes work by creating a partial vacuum above the liquid holding chamber and selectively releasing this vacuum to draw up and dispense the liquid, respectively.
Pipettes that handle between 1 and 1000 μl are generally referred to as micropipettes, while standard pipettes handle greater volumes of liquid. Two types of micropipettes are typically used in practice: air displacement pipettes and positive displacement pipettes. In particular, piston driven air displacement pipettes are pipettes that dispense an adjustable volume of liquid from a disposable tip. The pipette body includes a plunger, which provides the suction required to pull the liquid into the tip when the piston is compressed and released. The maximum displacement of the plunger is set by a dial or electronic interface on the pipette body, for example, allowing the delivery volume to be set. Whereas, for larger volumes, cylindrical pipettes (such as volumetric or graduated pipettes) are used and driven by a pipette aid or the like. Most pipettes are made of borosilicate, aluminosilicate, or quartz, with many types and sizes of glass tubing being available. Each of these compositions has unique properties that are suited to certain applications. Most micropipettes have a plastic housing for the air displacement components, a fitting post for a disposable plastic tip, where the tip may be provided in a variety of sizes and shapes that are designed for specific applications, as liquids are drawn into the tip. In most assays, tips are discarded after each individual use, usually via an integrated ejector mechanism.
Many common methods in biochemistry, molecular biology, clinical diagnostics, forensic science, combinatorial chemistry, etc. use standard manual micropipettes for the transfer of small volumes of liquid to and from various receptacles, including, but not limited to, standard 2-milliliter, 1.5-milliliter, and 0.5-milliliter disposable plastic sample tubes, standard 96-well microtiter plates, 384 and 512-well microtiter plates, PCR individual and strip tubes, and analysis devices, such as 1-D and 2-D gels, LC and HPLC microvials, etc. In each case, an operator handling the micropipette must carefully track the tip of the micropipette in order to deliver the reagent/solution to the correct location and do so without touching any other location, which would cause undesirable contamination. Many of the materials dealt with are clear or translucent, as are most reagents/solutions, providing minimal visual cues to the operator. Therefore, there is a need in the art for a practical solution for a researcher to efficiently locate the proper well to be addressed. The present invention is designed to solve this problem.